1. Technical Field
This invention relates to an apparatus and a method for a wireless sensor to monitor barrier system integrity, such as used or employed during sequestration of greenhouse gases.
2. Discussion of Related Art
Recent concerns regarding the environment and global warming are creating a desire and a need for sustainable energy programs while reducing emissions. Global warming may be linked to greenhouse gases. Greenhouse gases broadly include gases in an atmosphere that absorb and emit radiation within the thermal infrared range, such as carbon dioxide, methane, hydrogen sulfide, nitrous oxide, ozone, chlorofluorocarbons (CFCs), and/or the like. Power plants and other energy conversion facilities tend to be large sources of greenhouses gases emitted to the atmosphere.
Several possible solutions and alternatives are being proposed or developed to mitigate or reverse global warming. Carbon capture and storage or sequestration seeks to reduce emissions, such as by placing the carbon dioxide or other greenhouse gases into geological formations. Suitable geological formations generally have an overlying caprock of low permeability that may trap greenhouse gases and prevent them from migrating to underground sources of drinking water, the surface, and/or the atmosphere. Well designed sequestration systems maintain the seal integrity of the engineered borehole and the adjacent natural caprock seal even after the injection has stopped.
Injection of liquid waste into suitable geologic formations has been practiced for many years, such as hazardous waste disposed at deep well injection facilities. Deep wells inject the liquid waste into layers below impervious rock or clay.
Ciglenec et al., U.S. Pat. No. 6,766,854, discloses a wellbore sensor apparatus and method where the apparatus includes a downhole tool carrying at least one sensor plug for deployment into the sidewall of a wellbore. The apparatus is also used in conjunction with a surface control unit and a communication link for operatively coupling the sensor plug to the surface control unit. The sensor plug collects wellbore data, such as pressure or temperature of a hydrocarbon production formation, and communicates the data uphole via a communication link, such as the downhole tool or an antenna. Ciglenec et al. does not teach or suggest sensors for monitoring greenhouse gas sequestration systems. The entire teachings of Ciglenec et al., U.S. Pat. No. 6,766,854, are herein incorporated by reference in their entirety.
Schultz et al., U.S. Pat. No. 6,408,943, discloses a method and apparatus for placing and interrogating downhole sensors to passively monitor cement integrity within a wellbore in the hydrocarbon production interval. The sensors are “pumped” into place by placing them into a suspension in the cement slurry at the time a well casing is being cemented. The sensors are either battery operated, or of a type where external excitation may be applied to power and operate the sensor, which will send a signal conveying the desired information. The sensor is then energized and interrogated using a separate piece of wellbore-deployed equipment whenever it is desired to monitor cement conditions. Schultz et al. does not teach or suggest sensors for monitoring greenhouse gas sequestration systems. The entire teachings of Schultz et al., U.S. Pat. No. 6,408,943, are herein incorporated by reference in their entirety.
Negaley et al., U.S. Pat. No. 6,434,372, discloses a long-range communications apparatus utilizing modulated-reflector technology. The apparatus includes an energy-transmitting base station and remote units that do not emit radiation in order to communicate with the base station since modulated-reflector technology is used whereby information is attached to an RF carrier wave originating from the base station which is reflected by the remote unit back to the base station. Since the remote unit does not emit radiation, only a low-power power source is required for its operation. Information from the base station is transmitted to the remote unit using a transmitter and receiver, respectively. The range of such a communications system is determined by the properties of a modulated-reflector half-duplex link. The entire teachings of Negaley et al., U.S. Pat. No. 6,434,372, are herein incorporated by reference in their entirety.
Vinegar et al., International Patent Application Publication WO 01/65066, discloses a petroleum well having a borehole extending into a formation. A piping structure is positioned within the borehole, and an induction choke is positioned around the piping structure downhole. A communication system is provided along the piping structure between a surface of the well and the induction choke. A downhole module is positioned on an exterior surface of the piping structure and is configured to measure characteristics of the formation. The formation characteristics, such as pressure and resistivity, are communicated to the surface of the well along the piping structure. The entire teachings of Vinegar et al., International Patent Application Publication WO 01/65066, are herein incorporated by reference in their entirety.
There is a need and a desire to monitor barrier system integrity of greenhouse gas sequestration systems and/or other systems or wells. There is also a need and a desire for a sensor located outside of a casing of a borehole to detect changes in the surroundings and communicate with devices within the casing. There is also a need and a desire for a sensor to monitor barrier system integrity over long durations or spans of time associated with greenhouse gas sequestration. There is also a need and a desire for a sensor that can detect or measure characteristics not available with other wireless sensors deployed outside the casing, such as pH, porosity, conductivity, resistivity, the presence of or migration of carbon dioxide, hydrocarbon liquid, hydrocarbon gas, other geomechanical conditions, and/or the like. There is also a need and a desire for sensors that can be installed simply and cost effectively during drilling or in an existing well.